This invention relates to an apparatus and method for measuring the density of a liquid, using ultrasonic waves.
A method is known which uses ultrasonic waves to measure the density of a liquid. In the known method, ultrasonic waves are emitted to pass through a liquid of an unknown density, and the so-called "sing-around method" or the other methods are used to detect the period of time in which the waves pass through the liquid. Based on the period of time thus detected, the density of the liquid is calculated. With this method, however, the density of a liquid is erroneously measured due to the variation of external factors such as temperature.
It is an object of this invention to provide an apparatus and method which can accurately measure the density of a liquid, using ultrasonic waves, not affected by external factors.